DATEL ADS-942AME, ADS-942AMC Datasheet

® ®

REGISTERREGISTER

DIGITAL CORRECTION LOGIC

GROUND

GROUND

SUPPLY

3-STATE OUTPUT REGISTER

SUPPLY

GROUND

SELECT

SUPPLY

SUPPLY

FEATURES

• 14-bit resolution

• 2MHz minimum throughput

• Low-power, 2.2 Watts

• Functionally complete

• Internal reference and S/H amplifier

• 78dB signal-to-noise ratio

• Full Nyquist-rate sampling

• Small 32-pin TDIP

ADS-942A

14-Bit, 2MHz, Low-Power

Sampling A/D Converters

GENERAL DESCRIPTION

DATEL's ADS-942A is a functionally complete, 14-bit, 2MHz,
sampling A/D converter. Packaged in a 32-pin TDIP, the unit
contains a fast-settling sample/hold amplifier, a 14-bit
subranging (two-pass) A/D converter, a precision reference,
three-state output register, and all the timing/control logic
necessary to operate from a single start convert pulse.

The ADS-942A is optimized for wideband frequency-domain
applications and is fully FFT tested. The ADS-942A requires
±15V and ±5V supplies and typically consumes 2.2 Watts

+10V REF. OUT 1

OFFSET ADJUST 5

BIPOLAR 2

ANALOG INPUT 3

START CONVERT 32

EOC 16

OFFSET
CIRCUIT

S/H

TIMING AND

CONTROL LOGIC

4

SIGNAL

10

+5V

2

S

S1

DIGITAL

BUFFER

11

FLASH

12

+15V

REF

ADC

INPUT/OUTPUT CONNECTIONS

PIN FUNCTION PIN FUNCTION

1 +10V REF. OUT 32 START CONVERT
2 BIPOLAR 31 BIT 1 OUT (MSB)
3 AVALOG INPUT 30 BIT 1 OUT (MSB)
4 SIGNAL GROUND 29 BIT 2 OUT
5 OFFSET ADJUST 28 BIT 3 OUT
6 ANALOG GROUND 27 BIT 4 OUT
7 OVERFLOW 26 BIT 5 OUT
8 CODING SELECT 25 BIT 6 OUT

9 ENABLE 24 BIT 7 OUT
10 +5V SUPPLY 23 BIT 8 OUT
11 DIGITAL GROUND 22 BIT 9 OUT
12 +15V SUPPLY 21 BIT 10 OUT
13 –15V SUPPLY 20 BIT 11 OUT
14 –5V SUPPLY 19 BIT 12 OUT
15 ANALOG GROUND 18 BIT 13 OUT
16 EOC 17 BIT 14 OUT (LSB)

13

–15V

DAC

14

–5V

6, 15

ANALOG

8

CODING

31 BIT 1 OUT (MSB)
30 BIT 1 OUT (MSB)
29 BIT 2 OUT
28 BIT 3 OUT
27 BIT 4 OUT
26 BIT 5 OUT
25 BIT 6 OUT
24 BIT 7 OUT
23 BIT 8 OUT
22 BIT 9 OUT
21 BIT 10 OUT
20 BIT 11 OUT
19 BIT 12 OUT
18 BIT 13 OUT
17 BIT 14 OUT (LSB)

9 ENABLE
7 OVERFLOW

Figure 1. ADS-942A Functional Block Diagram

DATEL, Inc., 11 Cabot Boulevard, Mansfield, MA 02048-1151 (U.S.A.) • Tel: [phone] Fax: [phone] • For immediate assistance: [phone]

ADS-942A

® ®

ABSOLUTE MAXIMUM RATINGS

PARAMETERS LIMITS UNITS

+15V Supply (Pin 12) 0 to +16 Volts
–15V Supply (Pin 13) 0 to –16 Volts
+5V Supply (Pin 10) 0 to +6 Volts
–5V Supply (Pin 14) 0 to –6 Volts
Digital Inputs (Pin 8,9, 32) –0.3 to +V

DD +0.3 Volts

Analog Input (Pin 3) ±15 Volts
Lead Temp. (10 seconds) +300 °C

FUNCTIONAL SPECIFICATIONS

(TA = +25°C, ±VCC = ±15V, ±VDD = ±5V, 2MHz sampling rate, and a minimum 7 minute
warmup ➀ unless otherwise specified.)

ANALOG INPUTS MIN. TYP. MAX. UNITS

Input Voltage Range

Unipolar — 0 to +10 — Volts
Bipolar — ±5 — Volts

Input Impedence 2.3 2.5 — kΩ
Input Capacitance — 7 15 pF

DIGITAL INPUTS

Logic Levels

Logic "1" +2.0 — — Volts
Logic "0" — — +0.8 Volts
Logic Loading "1" — — +10 µA
Logic Loading "0" — — –600 µA

PERFORMANCE

Integral Non-Linearity

+25°C — ±1 ±2 LSB
0 to +70°C — ±1 ±2 LSB
–40 to +85°C — ±2 ±3 LSB

Differential Non-Linearity

+25°C — ±0.5 ±0.75 LSB
0 to +70°C –0.95 ±0.75 ±0.95 LSB
–40 to +85°C –1 ±1 +2.5 LSB

Full Scale Absolute Accuracy

+25°C — ±0.1 ±0.122 %FSR
0 to +70°C — ±0.12 ±0.36 %FSR
–40 to +85°C — ±0.45 ±0.85 %FSR

Unipolar Zero Error

+25°C — ±0.05 ±0.122 %FSR
0 to +70°C — ±0.1 ±0.2 %FSR
–40 to ±85°C — ±0.2 ±0.3 %FSR

Bipolar Zero Error

+25°C — ±0.05 ±0.122 %FSR
0 to +70°C — ±0.1 ±0.2 %FSR
–40 to +85°C — ±0.2 ±0.3 %FSR

Bipolar Offset Error

+25°C — ±0.1 ±0.2 %FSR
0 to +70°C — ±0.12 ±0.3 %FSR
–40 to +85°C — ±0.5 ±0.8 %FSR

Gain Error

+25°C — ±0.018 ±0.122 %
0 to +70°C — ±0.12 ±0.3 %
–40 to +85°C — ±0.6 ±0.8 %

No Missing Codes (f

14 Bits 0 to +70°C
13 Bits –40 to +85°C

Resolution 14 Bits

Footnote:

➀ Effective Bits is equal to:

➁ Same specification as In-Band Harmonics and Peak Harmonics.
➂ Two-tone Intermodulation Distortion (IMD) conditions:

in = 100kHz, 240kHz, fs = 2MHz, –0.5dB

f

in = 500kHz)

(SNR + Distortion) – 1.76 + 20 log

6.02

Full Scale Amplitude

Actual Input Amplitude

OUTPUTS MIN. TYP. MAX. UNITS

Output Coding Staight Bin./Offset Bin./2's Comp.

Comp. Bin./Comp. Offset Bin./C2C

Logic Level

Logic "1" +2.4 — — Volts
Logic "0" — — +0.4 Volts
Logic Loading "1" — — –160 µA
Logic Loading "0" — — +6.4 mA

Internal Reference

Voltage, +25°C +9.98 +10.0 +10.02 Volts
Drift — ±13 ±30 ppm/°C
External Current — — 5 mA

DYNAMIC PERFORMANCE

Total Harm. Distort. (0.5dB)

dc to 100kHz — –85 –76 dB
100kHz to 500kHz — –80 –75 dB
500kHz to 1MHz — –77 — dB

Signal-to-Noise Ratio

(w/o distortion, –0.5dB
dc to 100kHz 74 78 — dB
100kHz to 500kHz 73 75 — dB
500kHz to 1MHz — 73 — dB

Signal-to-Noise Ratio

(and distortion, –0.5dB) ➀
dc to 100kHz 73 78 — dB
100kHz to 500kHz 72 75 — dB
500kHz to 1MHz — 72 — dB

Spurious Free Dyn. Range ➁

dc to 100kHz — –86 –77 dB
100 to 500kHz — –81 –75 dB
500kHz to 1MHz — –78 — dB

Two-tone IMD ➂ — 85 — dB
Input Bandwidth (–3dB)

Small Signal (–20dB input) — 6 — MHz

Large Signal (–0.5dB input) — 1.75 — MHz
Slew Rate — ±250 — V/µs
Aperture Delay Time — — ±10 ns

Aperature Uncertainty — — 5 ps, ms
S/H Acq. Time, (to ±0.003%FSR)

Sinusoidal (fin = 1MHz) — — 150 ns

Step input (10V) — 250 450 ns

Conversion Rate

Sinusoidal (fin = 1MHz) 2 — — MHz

Step input 1.3 — — MHz

Feedthrough Rejection

(fin = 1MHz) — 85 — dB

Overvoltage Recovery, ±12V — 1000 2000 ns
Noise — 250 — µVrms

POWER REQUIREMENTS

Power Supply Ranges

+15V Supply +14.25 +15.0 +15.75 Volts

–15V Supply –14.25 –15.0 –15.75 Volts

+5V Supply +4.75 +5.0 +5.25 Volts

–5V Supply –4.75 –5.0 –5.25 Volts

Power Supply Currents

+15V Supply — +65 +80 mA

–15V Supply — –19 –35 mA

+5V Supply — +150 +175 mA

–5V Supply — –55 –65 mA

Power Dissipation — 2.2 2.6 Watts
Power Supply Rejection — — ±0.03 %FSR%V

PHYSICAL/ENVIRONMENTAL

Operating Temp. Range, Case

ADS-942AMC 0 — +70 °C

ADS-942AME –40 — +85 °C

Storage Temperature Range –65 — +150 °C
Package Type 32-pin, metal-sealed, ceramic TDIP
Weight 0.46 ounces (13 grams)

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